1. Field of the Invention
The present invention concerns a wheel rim and a method for making a wheel rim of the type suitable for use on an agricultural or construction vehicle, wherein the rim includes a rim ring for mounting a tyre and further including an at least two-part hub plate extending inside the rim ring, where the at least two-part hub plate includes a central hub plate including a number of holes and a contact surface for mechanical and detachable securing to a hub on a vehicle, wherein the central hub plate includes holes on a contact surface at the outer periphery for joining with a second hub plate with an inner periphery and an outer periphery, wherein the second hub plate at the inner periphery includes a contact surface with corresponding holes for joining with the central hub plate, where the second hub plate at the outer periphery includes holes for direct or indirect joining with the rim ring.
2. Description of Related Art
It is commonly known that wheel rims suited for use on construction and agricultural machines are made of steel with a rim ring and a with a hub plate. A typical design is that the rim ring is rolled in the wanted diameter and made with rim edges and other geometric shapes such that a tyre can be fitted thereon. The hub plate typically consists of a steel plate, either plane or shaped with one or more depressions. These depressions have partly the purpose of stiffening the hub plate and partly for bevelling the contact surfaces which are secured to a hub on a vehicle and to the inner side of the rim ring. The hub plate can often be mounted on the rim ring at various positions such that the position of the rim ring relative to the hub on the vehicle can be adjusted. This may be necessary if a tractor and an implement are to be driven between rows of crops on a field. By moving the hub plate between the various positions and by possibly turning the hub plate around, a plurality of different possibilities for changed wheel gauges are attained.
Another known adjusting possibility on such rims is the central part of the hub plate itself which advantageously can be replaceable as not all vehicle hubs are made with the same dimensions. Frequently there is a recess on the hub on which the rim bears via a central hole in the hub plate, and furthermore there are a number of bolt holes in the hub plate which are to fit bolt holes or bolts on the hub. By making the hub plate in two parts, the central part of the hub plate—the central hub plate—can be selected depending on which hub the wheel rim is to the mounted. For example, the central hub plate may have a central hole with a diameter of 390 mm, and ten holes with a diameter of 16 mm are disposed on a pitch circle with a diameter of 430 mm, corresponding to the actual hub. At the outer periphery on the central hub plate there may be provided a standardised hole pattern which fits all current hub plates. Thus it becomes possible to use the same rim on a plurality of different hubs just by replacing the central hub plate to one having proper dimensions. Central hub plates of the said type is often made of steel plate and may be plane as well as pressed with a depth.
However, many rims are made with a welded hub plate and with a central hub plate that can be turned around and which furthermore can be moved from one side to another of the welded hub plate in order thereby to adjust the wheel gauge of the actual vehicle. Alternatively, the central hub plate can be replaced by another one where the pressing depth is different. Respective hub plates are joined to each other by means of bolts with washers and nuts.
When a tractor or a contractor's machine is to be provided with wheel rims which either are or can be adapted to the desired wheel gauges, it is very often a request from the customer that the rims are to be delivered with a certain colour. In order to meet this demand, it is often required that the rims and hub plate initially are to be painted. If a dealer of wheel rims wants to shorten the delivery time, he is actually required to have a disproportionately large stock of prefabricated rims of different dimensions and with different types of hub plates and not the least a plurality of different colours. By having this large stock, where part of or all rims may be painted in the most current colours, a reasonably short delivery time can be achieved. However, typically it appears that this large stock is not attractive for the supplier as orders for making wheel rims and/or hub plates that are not in stock frequently occur anyway.
Another drawback of the prior art solutions is that the hub plates are made with a central hole wherein along the periphery of the hole is located a plurality of holes corresponding to similar holes in the central hub plate made with a diameter about 60 to 100 mm greater than the central hole in the hub plate. In other words, there is a relatively large waste of material as the material in the central hole cannot be used but has to be discarded.
From U.S. Pat. No. 4,279,446 is known a solution to an adjustable wheel rim where between the rim ring and the hub there is arranged a multi-part hub plate which in principle consists of a plurality of uniform parts arranged releasably in continuation of each other between hub and rim ring on elevations adapted for the purpose on the rim ring itself. Thus it is so that a multi-part hub plate can be moved between various positions on a rim ring. In no way it is here envisaged how the design of the individual parts should be in relation to each other in order to achieve a minimal consumption of material and simultaneously achieve a minimal number of work processes. Furthermore, it is a rather cumbersome solution as it is not readily possible to change the pressing depth of a wheel rim into another, and not at all into a third value.
From US 2008/0054714 A1 it is known with another solution wherein a hub plate can be mounted at a first or a second side of a fitting on a rim ring. Also, the hub plate can be reversed, and hereby four different pressing depths are enabled on such a wheel. Not in this solution either there is thought about minimising material consumption or to achieve a minimum number of work processes, neither during production nor during use.